Light metal wheels of motor vehicles, customarily called alloy rims, are coated in surface treatment systems comprising a powder or another coating material. Then the coating is stoned in an oven. For this purpose, the vehicle wheels are transferred from a coating station to an oven. Vehicle wheels made of other materials, in particular steel wheels, are also treated in successive operating steps. In general terms, vehicle wheels have to be transferred from one operating station to another operating station regardless of their material.
For this purpose, handling modules of the type mentioned at the outset which are known from the market are used, and to this end these are fastened to a multiaxial robot arm so that transfer may be performed with as many degrees of freedom of movement as possible.
In known handling devices, all the vehicle wheels received thereby are kept immobile in relation to the handling device; it is not possible to alter the position of the vehicle wheels later in relation to, for example, the frame structure.
However, every vehicle wheel has structural tolerances which may result in two vehicle wheels that are gripped by the handling module at the same time having different overall heights. This may have the result that the transfer from one operating region to the next is not performed as precisely as is wished. If for example vehicle wheels are deposited on horizontal carrying structures, the placement regions of the vehicle wheels, at which they are deposited on these carrying structures, should ideally lie in a common horizontal plane.
It is thus an object of the invention to provide a handling device of the type mentioned at the outset which takes account of these ideas.